When a fan is turned off, its angular speed decreases from 10 rad/s to 6.3 rad/s in 5.0 s. What is the magnitude of the average angular acceleration of the fan?
A) $0,74 \mathrm { rad } / \mathrm { s } ^ { 2 }$
B) $1.2 \mathrm { rad } / \mathrm { s } ^ { 2 }$
C) $11 \mathrm { rad } / \mathrm { s } ^ { 2 }$
D) $0.37 \mathrm { rad } / \mathrm { s } ^ { 2 }$
E) $0.86 \mathrm { rad } / \mathrm { s } 2$

Question

When a fan is turned off, its angular speed decreases from 10 rad/s to 6.3 rad/s in 5.0 s. What is the magnitude of the average angular acceleration of the fan? 
A) $0,74 \mathrm { rad } / \mathrm { s } ^ { 2 }$
B) $1.2 \mathrm { rad } / \mathrm { s } ^ { 2 }$
C) $11 \mathrm { rad } / \mathrm { s } ^ { 2 }$
D) $0.37 \mathrm { rad } / \mathrm { s } ^ { 2 }$
E) $0.86 \mathrm { rad } / \mathrm { s } 2$

Quizplus · Accepted Answer

The average angular acceleration is given by:$$\alpha = \frac{\Delta \omega}{\Delta t} = \frac{6.3 	ext{ rad/s} - 10 	ext{ rad/s}}{5.0 	ext{ s}} = -0.74 	ext{ rad/s}^2$$The magnitude of the average angular acceleration is:$$|\alpha| = |-0.74 	ext{ rad/s}^2| = 0.74 	ext{ rad/s}^2$$Therefore, the correct answer is A.

When a Fan Is Turned Off, Its Angular Speed Decreases 0,74rad/s20,74 \mathrm { rad } / \mathrm { s } ^ { 2 }0,74rad/s2

When a Fan Is Turned Off, Its Angular Speed Decreases $0,74 \mathrm { rad } / \mathrm { s } ^ { 2 }$